A: CT chest/abdomen/pelvis with examination +/- imaging of the breasts (in female patients) and testes (in males), to find any evidence of malignancy elsewhere. Also MRI head with contrast for further evaluation of the lesion, and for any other smaller foci not detected on CT.

Appearances, with unremarkable staging CT and with the lesion crossing the midline, favor a high grade glial series tumor.

3 case question available

Q: Given the cerebral findings, and lack of a primary on the body CT, what is your favoured diagnosis?
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A: An aggressive ring enhancing lesion, which crosses the midline, is suspicious for a high grade glial series tumour, probably GBM. Ependymal involvement is a poor prognostic marker.

Q: If there was marked central high DWI signal with corresponding low ADC values, does anything else enter your differential?
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A: Increased restricted diffusion indicates reduced extracellular space, either due to swollen cells or too many cells per voxel. Tumours do not typically restrict (lymphoma and medulloblastoma do), so abscess should be considered. However, this is not the situation in this case.

Q: What histopathological results from the biopsy might affect treatment?
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A: MGMT is a DNA repair enzyme. If this is methylated (on genetic testing), then there is a better response to some chemotherapeutic (alkylating) agents. Low grade gliomas tend to be methylated, while higher grade gliomas, as in this case, are unmethylated, usually with limited response to chemotherapy. This patient proceeded to undergo radiotherapy alone.

Case Discussion

Initial treatment was with oral steroids and the case was referred for tertiary opinion.